Multi-beam generating element and optical printing apparatus therewith

Abstract

A multi-beam generating element generates an even number of multiple beams having a uniform light intensity. The multi-beam generating element has a grating constructed by repeatedly arranging basic phase patterns, wherein the basic patterns are composed of at least two kinds of rectangular patterns having non-uniform widths and different phase heights. The basic phase patterns are fabricated by superposing rectangular patterns having non-uniform widths and single phase heights to form a multi-layer arrangement. In an optical printing apparatus having the grating, the multiple beams coming out of a multi-beam generating element are applied to a multi-channel acousto-optical element, a Dove prism rotating the angle of the aligned direction of the multiple beams having light intensities which have been modulated, and then the beams are scanned with a rotating polygonal mirror. By employing a grating generating multiple beams having uniformity in light intensities, a high speed and high resolution optical printing apparatus can be attained.

Dependencies are inferred from the claim text.